I. Field of the Invention
The present invention relates to a firearm with a closing device of operative side ports of a receiver, in particular of ports situated on the right, left, or on both sides of the receiver.
II. Description of Related Art
Operative ports are suitable for allowing the movement of components protruding from the receiver, generally connected to the bolt, such as, for example, a cocking handle in repeat firearms.
The cocking handle, connected to the bolt-slide group, must be moved manually into its most withdrawn operating position at least for the loading of the first cartridge from the magazine. The cocking handle returns from its most withdrawn position together with the bolt-slide into its most advanced functional position due to the recoil springs of the bolt assembly.
On the contrary, in the case of an automatic firearm, after the first shot, the withdrawal and advance run of the bolt-slide takes place autonomously.
The run of the bolt-slide and cocking handle integral therewith varies according to the length of the cartridge. The operative openings in the receiver and their total length must consequently take these parameters into account.
In most repeat firearms, for ergonomic, mechanical and functional reasons, the cocking handle is situated close to the front end of the ejection port of the cartridge cases. In this case, the ejection port is also contemporaneously part of the operative port of the cocking handle.
As the ejection port is not sufficiently long enough to allow the run of the cocking handle, however, at a rear end of the ejection port there is generally located a slit opening in the receiver as an extension of the ejection port.
For the correct functioning of the firearm, it is important for the slit opening, and also the ejection port of the receiver, to be as closed as possible to prevent the functioning of the firearm from being unacceptably jeopardized under unfavourable environmental conditions, such as sand, dust, snow and the like. These disturbing factors could in fact be freely introduced through the port inside the firearm and in particular near the main components, such as for example, the bolt and firing pin, causing disturbances in the functioning of the firearm and at the worst damaging it.
In the case of the ejection ports, these are closed for every reloading operation by the same bolt-slide.
For the other operative ports of the cocking handle, a solution could be to lengthen the bolt-slide to allow this in its movement to also cover the slit openings. This solution however would require a lengthening of the receiver which would consequently lead to an increase in the length of the arm and therefore its weight.
For this reason, firearms of this type are generally equipped with various kinds of closing devices applied outside the receiver.
The use is known of a cover which can be moved along rails by means of the cocking handle, which, upon withdrawing, overcomes the force of a recoil spring, which is constrained to the cover. During the withdrawal of the cocking handle, it is the same cocking handle which moves the cover freeing the slit opening. When the handle is disengaged from the slit during the advance run, the recoil spring brings the cover back into its starting closure position of the opening.
In another known solution, less commonly used, two rubbery closing lips are assembled parallel to the slit openings for their whole length. When the cocking handle, in its withdrawal, enters the area of the elastic closing lips, it deforms them and moves them to complete its trajectory. When the cocking handle, in its advance run, abandons the area of the lips, these return to their original position to reclose the slit openings of the receiver.
This movement or deformation process is effected for every shot. The above-mentioned components are therefore among those which are subject to most stress and are consequently made of high-quality materials.
A first drawback of the known devices consists in their cost, the cost of the additional constraining elements, the assembly costs and also maintenance costs.
These costs are doubled above all for ambidextrous firearms.
A further disadvantage of the above devices of the known art consists in the considerable problems relating to reliability, particularly serious under critical environmental conditions in which functioning without blockages of the firearm is particularly important.
Due to sand, dirt or ice on the rails there may in fact be problems in the withdrawal of closing devices with a cover as the recoil spring may not have sufficient force. Hindrance problems however prevent the production of recoils springs having a greater force reserve.
The production of elastic lips also has problems of reliability with time, as the elasticity of the lips is reduced and they become cracked and fragile and are no longer capable of exerting their closing function.
A further drawback of the known devices described is that energy is taken from the bolt to activate the closing, thus reducing the force reserves.